If a horizontal line has the equation
f(x)=a and a vertical line has the equation
x=a, what is the point of intersection? Explain why what you found is the point of intersection.

The point of intersection is
(a,a). This is because for the horizontal line, all of the
y coordinates are
a and for the vertical line, all of the
x coordinates are
a. The point of intersection is on both lines and therefore will have these two characteristics.